The invention relates to a container for treating lumpy or grained materials in a packed bed with gaseous media, wherein an opening of the container can be closed by a lid.
Particulate materials, such as e.g. lime or magnesite, dolomite, are treated for various purposes in various ways, such as being heated, cooled, dried, smouldered, roasted, sintered, burned or reduced. With these methods of treatment, a gaseous medium is guided through the grained material at a certain temperature and possibly under elevated pressure. The types of treatment listed as examples differ from one another in temperature, pressure, heat required or occurrence of heat, respectively, and the duration of treatment.
Numerous devices have been known for the treatment of grained materials with a gaseous medium. Thus, for instance, for treatment at high temperatures (up to approximately 1500.degree. C.), such as roasting, sintering, burning or reducing, shaft furnaces or retortes, revolving cylindrical furnaces, burning plants or a combination of these devices are used. All of these devices, however, have the disadvantage that they are suitable for certain materials or certain kinds of treatment only.
A shaft furnace or a retorte, e.g., is not suited for sintering, since the sintered material cannot be carried out. Also a material which is not sufficiently gas-permeable because of its packing density cannot be treated in these devices. Furthermore, it is difficult to subject the material to be treated to an intermediate treatment, and it is also difficult to control the treatment process.
A revolving cylindrical furnace can be used for a greater number of purposes, yet the cost of investing in such a furnace is very high. A further disadvantage consists in that it is uneconomical as regards its thermal economy. Additionally, process changes in wide ranges can be carried out only over a long period of time.
It has been known to use travelling grates for treating grained materials. Such travelling grates are formed by grate cars joined together to form a continuous chain that continuously travels through a furnace. When the treatment temperatures are high, there is a danger that the grates will become overly deformed or even destroyed, since the treatment gases are also pressed or sucked through the grate. When the treatment temperatures are very high and the periods of treatment are very long at the same time, such as is necessary when calcinating limestone, travelling grates are not suitable. But travelling grates are also not suitable for methods of treatment carried out at low temperatures, for which high pressure differences are necessary (e.g. for the drying of coal), since it is not possible to maintain high pressure differences with these grates.